Rowan, Types and Species Names of Mountain-ash Trees

Rowan Trees are part of the genus Sorbus, subgenus Sorbus. Rowan trees form most of this group, and a few species in North America locally known as "Mountain-ash" (but not related to the Ash Trees) make up the rest of this group (Sorbus, subgenus Sorbus). Most Rowans are small flowering deciduous trees 10 to 20 m (33' to 66') tall, some species like Dwarf Rowan Sorbus reducta grow as shrubs however.

Types of Rowan;

Some well known species of Rowan include; European rowan Sorbus aucuparia, and Japanese Rowan Sorbus commixta (Japanese: ナナカマド （七竈）). Some well known species of Mountain-ash include; American Mountain-ash Sorbus americana, Showy Mountain-ash Sorbus decora, Sitka Mountain-ash Sorbus sitchensis.

Rowan Leaves, Flowers and Fruit;The leaves of Rowan and Mountain-ash trees are arranged alternately, are pinnate, with (7-)11-35 leaflets, and a terminal leaflet is always present. Flowers of the Rowan trees are borne in dense corymbs, flowers have five cream white petals, about 5 to 10 mm (0,13⁄64" to 0,25⁄64") across. Rowan fruit is a small pome 4 to 8 mm (0,5⁄32" to 0,5⁄16") in diameter. The pome colors vary among species, most are bright orange or red, others are pink or yellow, and some Asian species are white. Rowan fruit are juicy and soft, making them very attractive food for birds.

Uses for Rowan Trees

Rowans do well as small ornamental trees for landscaping parks, gardens, avenues, boulevards and wildlife areas. These trees are very attractive to fruit-eating birds, so bear in mind that you will have birds visiting these trees frequently if you use them.

Ornamental looks;Some popular types of Rowan include the Chinese native species, such as Sargent's rowan (Sorbus sargentiana) for its exceptionally large clusters of fruit, and White-fruited rowan (Sorbus glabrescens) for their unusual fruit color. Many cultivars have also been selected for landscaping use, for example the yellow-fruited Sorbus 'Joseph Rock'.

Rowan trees naturally produce numerous hybrids, amongst themselves and with the Whitebeam trees (these are variably intermediate between their parents but generally more resemble Whitebeam trees and are usually listed with them). Some hybrids between Rowan and Whitebeam trees will start behaving as true species reproducing by apomixis.